M 
stereophotogrammetry was demonstrated shortly afterwards 
(Hasselwander 1954). In the succeeding seventy years, many 
contributions have been made io this area, particularly by biomedical 
investigators and photogrammetrists from Germany. A number of 
relevant publications have also emanated from Swedish laboratories and 
clinics. Fortunately, the books and monographs of Lacmann (1950), 
Hasselwander (1954), Halleri (1970) and Lôschner et al (1970) provide 
ubstantial documentation of this work. The large number of articles on 
X-ray stereophotogrammietry makes it impossible to recount the details 
here, but the attached reference list should constitute an ample survey 
for most purposes. 
À noteworthy development is the recent introduction of an x-ray 
stereoplotter by Carl Zeiss Oberkochen (Kellner and Janke 1971, Meier 
1972) ss a standard product line. As in so many areas of biomedical 
stereophotogrammetry, manufacturers have done little to meet the need 
for special x-ray stereophotogrammetric equipment and, therefore, the 
initiative taken by Zeiss Oberkochen and their colleagues at G&ttingen, 
who promoted interest in this development, is highly commendable. 
5.2 Ultrasonic, Infrared and Other Forms of Stereometric Imagery 
There is a growing interest in the potential of ultrasonic techniques 
(including ultrasonic holography as discussed in another section of the 
review) to supplement x-ray methods of examining the internal anatomy 
of animals and humans. Recent articles by Korpel (1968), Ensminger 
(1969), Waxham (1970), Arehart (1971), Kessler, Korpel and Palermo 
(1971) and Lewin (1971) describe a wide variety of prospective 
applications. Unfortunately, only a few articles to date have been 
addressed to the stereometric quality of ultrasonic imagery. 
Stouffer (1968) studied the feasibility of using ultrasonic 
equipment to produce cross-sectional maps of living humans. 
Comparative analysis of direct cadaver measurements with values 
obtained by ultrasonic scanning revealed a need for improved resolution 
and spatial sensitivity. Makow and McRae (1968) described the metric 
capabilities of ultrasonic brain analysis and the limitations imposed by 
such problems as multiple reflections within the bones of the skull. 
Boyer et al (1971) recently developed a potentially better technique for 
quantitative ultrasonic imagery, but further research and development is 
necessary before this or any other direct ultrasonic scanning approach 
yields imagery of high spatial quality. Of course, high spatial quality is 
not a sine qua non for all biomedical applications of stereometric 
analysis, it is only necessary to have adequate spatial quality for the 
purpose at hand. What is "adequate" will be determined by knowing the 
levels of accuracy and precision required in each application. 
Although the subject has often been discussed, infrared 
stereophotogrammetry seems to have received little or’ no serious